Approximately 20 major malformations have been identified from the malformations registry data base for future investigations. Staff have been recruited in New York State and the protocol has been developed by investigators from NICHD, The New York State Dept. of Health, and NHGRI. Cases with the major birth defects of interest have been selected from the Congenital Malformations Registry along with suitable control subjects. Data from the Registry have been linked with the State's newborn screening program to identify filter paper samples for the first group of subjects. The filter paper samples are being taken from storage and the process of DNA extraction and aliquotting will begin soon. Concurrently, the investigators have begun identifying defects of interest for the first series of studies and selecting candidate genes of interest and variant single nucleotide polymorphisms (SNPs). The process of selecting a laboratory for SNP genotyping is almost complete; the first choice laboratory is being evaluated by sending test samples.